got the same problem as you, i think it's because of your mood/mental state.

I feel that how a training session goes is really dependant on your mental state. For example, in days where i feel very happy, light, peaceful, i tend to train really well and smooth. Everything seems to go right and my body is able to work at a high pace for the entire session.

However, days where my mood is bad, when i feel like **** or a little depressed, the training sessions start to be plagued with fatigue and the performance levels drastically decreases.

In your case the stress coming from school could be your cause.

Hopefully after the 2 weeks left your performance will go back to its previous level! In future however, you may face similar situations so you got to find a solid solution to it.